What causes the lithospheric plates to move

convection currents in the mantle

Explanation:

Convection currents in the mantle are always moving, and make the plates move too. The plates are resting on top of the mantle, which is where the convection currents are, which make them move along with the magma.

well in order to answer this question you have to provide more information < 3

let that person have a turn to speak : )